I had the same issue with fronts after one autox. Installed the day prior, drove to the site 30ish miles, 6 runs, drove home. Bearings were making a horrible noise. Jacked the car up and wiggled the front wheels..though I had forgotten to tighten the lug nuts it was so bad. Still regret I didn't take video. It was unbelievable...

Other sets with street miles I've gotten about 1 1/2 seasons out of.

I've taken the approach of throwing the cheapest bearing I can find at it....none seem to stand out as better than the next. I do have a few sets of the rear roller bearing variety which I want to experiment with replacing the inserts.

What seems to make a difference for *me* is breaking bearings in with gentle street miles.

Not sure this will help, but something to check..

Did the brake hold prior to replacing the cables?

I replaced the parking brake cables on my 89 with aftemarkets. Parking brake didn't hold. Troubleshooting finally led me to compare length of the new cables against the old (factory originals). Replacements were slightly longer than the originals...parking brake wasn't engaging completely. Re-installed the originals; at least gets me an annual inspection sticker

MIBearings with 370 miles.

I cleaned the stub splines with a wire brush and brake cleaner. Sprayed a little WD-40 on the shaft when I installed the bearings. Torqued the nut while the car was in the air - stuck a punch through the brake caliper into the vented rotor to keep it from spinning.

New bearings, torqued to 180 lb/ft. Old nut, new crown, washer, and cotter pin. Cleaned the splines on the stub with a wire brush and brake cleaner.

I did get new nuts from Rock Auto, but they didn't seem correct when I tried to put them on. Maybe that's the pinch Bogus is referring to? I'll try to install those nuts.

Glad I can wrench on my own car!

Any one else have problems with the rear hub nut loosening - the large nut that secures the stub shaft?

It's become habit for me to carry a torque wrench and socket to re-torque the nut, sometimes daily. I think the remaining vibration I'm feeling - and part of the reason I procrastinated on checking tires - may be the rear hubs loosening up.

Any solutions/suggestions for keeping the nut tight? Lock nut, chemical locker (loctite), real castle nut, double nut, just deal with it?

Tires.

BillH nailed it in post 2!

Put a different set I had lying around on and went for a ride. Noticable difference as soon as I pulled out of the driveway.

It's not silky smooth, but vibration is mostly gone.

Thanks again!

Sorry I haven't posted lately - life (work, fam etc) kinda gets in the way sometimes, lol...

Vibration is worst at around 50mph...get it to 60-65 at least is't bearable. Sorry officer, you see, I have this vibration at 50....

Probably won't have any time available to do more serious work for a while, but I still need to get the tires balanced.

Brian's correct - no Banski for me, although I'd love to run Tom's stuff. Maybe, maybe poly and jump to BSP depending on the quality of used stuff available, since that seems to be the only option.

Thank you again for all the suggestions...still working.

Feeling a little silly...

Bushings on the left side strut (camber) rod are SHOT!

(inner bushing rubber torn, outer bushing metal sleeve out of round, i.d. opened up - lots of play)

Wheel bearings new on April 4.

I read the thread on u-joints. I chucked a wire brush in a drill, cleaned out the bore and groove and re-installed the e-clips. Took some measurements with a machinists rule and discovered the yoke was spread slightly. Put some light machine oil on the cups at re-install to make them go in a little easier, and a little work with a 3-pound hammer got the u-joint to rotate freely.

Both u-joints looked good, but I replaced the front joint for good measure. I didn't see the tip about replacing the grease until I had re-installed the shaft.

Re-installed the prop shaft and noted the vibration was improved - didn't shake as much from the center, but still some serious shaking out back. Seems a bit worse under accel around 50+ - a little better under steady state, gets worse again under decel. Not a big change in vibration, but enough that I think I am feeling a bit of a difference.

Next I'm going to try one half shaft at a time. At this point, it's easier for me to mess with u-joints than get the tires balanced.

Pulled the main prop shaft. Front u-joint at the slip yolk is smooth on one axis, notchy on the other. I'm going to replace the u-joint and continue on...

U-joints are new-ish, 3 years maybe.

Dealt with a few other items I found underneath - exhaust hangers, grease joints and bushings..squirrel!

Road tested the car to pay closer attention to when the vibration occurs. About 30-35 on up...little worse in 6th, but definitely seems to be related to final drive speed, not engine RPM. Pretty bad vibration.

Sorted the other items because I'd like to take a good look at the drive shafts - maybe remove them and take them to a shop for inspection. That won't happen for a couple of weeks.

Would anything in the diff. cause bad vibrations?

So, balance the tires, pull and inspect drive shafts...

Thanks Brian...

I lurk here a lot...great people and information. Reminds me of the F-body board I used to frequent.

Oh, and it can't get much colder than the last (first SCCA) event! In case anyone's wondering, mid-40's, stiff, relentless wind all day and at one point - a light sleet shower. No worries however, in 6-8 weeks it'll be 90+ at Devens...

Bill..I'll get the tires checked. I ran it through the gears, again with out the tires. Vibration seems at its worst right around 80mph in 4th, 5th, and 6th.

While the car is up, I might try to pull the prop shaft and give it a look-see.

1989 6 speed. All stock suspension (no poly, rod ends, etc.)

I have a pretty strong vibration that seems to come from back of the car...

I've read through a few threads here and so far tried...

1. Jack up the rear and put it on jack stands.

2. Ran the car through the gears - see what/when it shook.

3. In 1st at idle, I noticed both rear tires appear flat spotted, so I removed one at a time. Vibration got better each time, but still there when I gave it some throttle.

4. Took a glance at the drive shafts - didn't see any obvious vibrating. Not too in depth at this point I know, just looked for any obvious trouble.

5. Ran the car up through the gears to ~2,500rpm - fairly smooth in 1-5, but in 6th at 1,800rpm ~83mph - jackpot!

I'm going to take a break from it and go back and try different speeds, different gears - see if I can narrow it down.

Any ideas, thoughts, avenues to pursue would be appreciated.

SOB - how'd you know that was my nick name for it?

Anyone have a parts fiche with a part number for the front lower LCA bolts and nuts?

Interested in the full set. Are they operational? Work in an '89?

Thanks!

There was no tension on the bolt. I was in the process of replacing the front spring.

In the end I had to cut the bolt on either side of the bushing with my trusty sawzall.

Bolt was definitely frozen in the bushing tube. Pressed the remains out with my 20T HF press. Looks like that bolt had been replaced at some point. It did not have a reduced dia shank like the original front did. Probably contributed to the corrosion issue. That, and 23 years in the rust belt.

Thanks again for the suggestions.

(HBD Guru!)

I can not get the bolt to move rearward at all.

It seems as if I need to cut the bolt in two places, between the bushing and frame mount and pull the arm off with the center portion of the bolt still inside the bushing.



Thanks!

Feel kinda silly asking, but does any one have tips on removing the rear bolt from the front lower control arm? The nut is off, bolt spins, but it won't slide out.

Trying to drive it out with a punch isn't doing it.

Thank you.....

Jeff

Just cleaning it will be then.

Thank you for the replies!

I'm getting ready to swap out the front spring. What, if anything, should I use to lube the a-arm seat, or should I just make sure it's really clean?

Any other tips/hint/suggestions would be appreciated as well.

TIA...

Jeff

Where did you get the compressor? Same thing here, compressor failure. Pulled the orifice tube, full of metal shavings

Thank you gentlemen for the reply. I'll order me up a couple of bolts.

The bolts at the flange were rusted enough and heads rounded off enough that it was easier to cut the bolts and get a hold of what was left with vice grips after applying heat. Impatience was getting the better of me.

The good news is the diff innerds looked pretty good, given it's 22 years old and pretty much has been driven only on Sundays most of its life ;-) - since the early-mid 90's or so. One of the off-season winter projects..

Thanks again!

Jeff

Any one off hand know the bolt dia, thread pitch, length of the bolts that attach the y-pipe to the rear of the cat on an '89 L98 car?

Cut the cat-back off to facilitate removing the diff. I'm sure by the time I get the remains out with the hot wrench and vice grips they won't be in the best of shape to get a size off.

TIA,

Jeff

Frequent lurker, occasional poster. I gotta get me an avatar and participate more....

Happy New Year, Gurus

I've got two sets - might be good for chess pieces?

Like many, my parking brake would not hold the car. The handle would pull all the way up with little resistance.

New rear calipers, pads, rotors. Fairly new brake cables - OE right rear was sticking so I replaced all three. The plastic piece that holds the front cable to the adjuster did break previously; the handle is a replacement and the mechanism in good condition.

I spent hours tonight knocking a big hole in the wall with my head trying to figure it out - studied the FSM cartoon, searched every corvette board I could find, google, bing, etc. The searches turned up lots of results with similar problems but no one ever followed up with solutions. I figured I'd post up my solution hoping to spare someone else some grief.

I finally retrieved the old set of cables I had kept lying around. Compared the length of the original rear cables left and right, both the same length. Compared an original rear cable to the rear replacements I installed - same length. Next, I removed the replacement front cable from the car and compared it to the old, stock cable. Different lengths!!!

I assumed.....



Since the OE front cable was still operational, I put it back on the car. Parking brake works great.

I don't recall which Corvette vendor I purchased the cables from - either Ecklers or Midamerica - and it probably doesn't matter. This is not, and should not be taken as, a slam against either vendor. I've had great luck and service from both. Ecklers in particular over-nighted a part I was in dire need of that got me out of a tight spot. I'd suspect both source the part from the same manufacturer. The message is, no matter the source, be sure to check your replacements against the OE to make sure they are the correct length before you install them.

Not to hyjack the thread.......

I think it could work.

I've felt the source of the C4 drone is the Y intersection post main cat, where the single pipe out of the cat branches off into two pipes. No real hard data to back this up, but my theory is turbulence at that point causes the drone.

I had a single 3" pipe off the cat through a resonator put on my car - primarily for weight savings - but also to test the theory. Plenty of power, mileage went up, and no drone at cruising speeds. Still a little noisy but it doesn't have that annoying drone and I can hear the radio and myself think; a muffler vs a resonator might help with the noise.

Looks like this muffler works on the idea of cutting back on reversion - air running back down the pipe. Valve opens to let air out, closes to prevent air from entering.


Thoughts?

IIRC, my car wasn't setting any codes.

CAGS and upshift light wouldn't work either.

Took the car to the dealer - the ECM wouldn't communicate with the scanner.

Replacement computer was cheap enough at advanceauto - local, they had one in stock - that I just swapped it out. Was cheaper than the dealer diagnostics charge and it worked fine. Going on two years now.

Sorry, rear hubs are two weeks old. This is the second wheel/tire combo this has happened to. These tires were mounted up on these wheels when I changed the tie rod ends. I was hoping the new tie rods ends had cured the problem.

I do notice a difference with the tie rods and hubs.

I think just about every part in the rear is going to be replaced before all is said and done. Each part replaced makes a difference - new tie rods, car stopped wandering on accel/decel, new hubs, roughness and noise went away. I know it needs a new pinion yoke - I have one sitting in the garage from Randy's R&P.

Sorry if I'm omitting a lot of details - been frustrated for a while with this. Thanks for the help and suggestions thus far...much appreciated.....

I can't see the tire hopping - I'll try to get someone to follow me or drive beside me and look at it. I sure does feel like the tire is moving a lot. The wear pattern was feathered across the center tread blocks.

U-joints are new, within the past year, both outer tie rod ends with in the last two months.

Shocks passes a basic push test and show no signs of leakage. I know, not real accurate or scientific, but the shock doesn't feel especially worn. I'd think if the shock was bad enough to be the sole cause, it would be noticeable with a basic push test. Rebound adjuster - Koni single - still functions in that I can see a change in extension when I fiddle with the knob.

When I got the car, this is what happened to the RR outer u-joint...

RR Outer U-joint

I suspect that's when a lot of the problems began.

Vibration increases with road speed. What I think the "vibration" is - maybe my description isn't very good and may be misleading - is the tire either shaking back and forth or hopping up and down like a basketball.

Real bad.....

Top hole is similar. The sleeve in the bushing the bolt passes through has a similar elongation, more so on the bottom bushing than the top.

I've been chasing a bad vibration/tire hop in the rear. Put tires on it mid-January. Fronts look brand new, rears are smooth.

Think this could be the cause, or most of it?

RR Lower Dogbone mounting hole

When my ECM - 1989 - was bad, the instant and average MPG, and range functions didn't work. The car wouldn't idle under 1200 either. I didn't get a code 51, but neither could the ECM be accessed with a scanner.

No problem with pointing out the obvious - I freely admit I can be "blind" at times, or is it blonde?

The RR wears faster than any other corner, LR almost as fast - probably in part due to an aggressive alignment driven on the street.

Something tells me I've chased out of balance wheels before and that wasn't it. Good suggestion, though. I'll try rotating tires around tomorrow and see what I get.

When I replaced the u-joints one was bound up so badly it wouldn't rotate at all and the cap broke from the strain. Somehow in my mind I want to relate some of my trouble back to there. It was the RR outer u-joint.

[img width=300]http://www.facebook.com/#!/photo.php?pid=30366643&id=1018720494[/img]

I also have an issue with the pinion yoke. U-joint is loose in the register. I measured u-joints and the yoke with calipers, I know I need a yoke, which means crush sleeve/pinion bearing preload is compromised, which means pull the diff....

At low vehicle speeds and lower gears - especially 6th, every once in a while I'll hear a fairly loud clunk when I get back on the gas from decel, best I can relate is a backlash kind of clunk. Rotating the half shafts by hand I get a good bit of play at the diff housing and clunking. This is the only IRS D44 I've ever been around, so I don't know what's "normal".

The shin bone's connected to the thigh bone, the thigh bones...

Alright, I put the Napa bearings on - (made in China BTW). Left side came off the stub axle with hand pressure and in one piece. Yes, bad RR hub.

As for symptoms, it sounds quieter back there - not that a C4 will ever be quiet - and feels a little tighter, less twitchy.

As for my vibration, I'll call it improved but not fixed. Feels more central. With the new RR hub, I don't feel shaking center-right, just center. I have a feeling I'm gonna need all new bearings in the diff as well as bushings in the rear before all is said and done. Too bad stock replacement bushings are made of unobtainium.

I could get to mine using jack stands.

What symptoms were you having? Grinding noises, clicking, vibrations, play?

Brian,

It's a generic puller with 3 arms 120* apart (can be converted to a 2-arm), it hooked around the wheel flange with the center bolt bearing against the stub axle.

I had heard of the rears coming apart before. Thank goodness for that nut on the axle, which makes periodic inspection by shaking the wheel a little difficult.

That makes the tally 1 rear hub on the vette separated, 1 front hub on the f-body broken (the little stub of an axle snapped during an autocross run).

Since I need the car, I ordered a pair of rear hubs from the local Napa store.

I didn't think I could get enough umph with just a 3-jaw and 1/2 drive breaker bar to separate a bearing.

I ordered the washers a while ago in anticipation. They've been sitting on a shelf waiting. I've probably seen some of your threads referencing the washers before - probably what prompted me to order them in the first place.

Since it's still a DD, I can get a few miles on the hubs before the first autocross of my season on April 11.

I know people have posted pics in the past of disassembled hubs, but I've never been able to view any. What holds it together?

I'm chasing a bad vibration in the rear so I though I'd start easy (bearings)and work hard (diff).

Tried to remove the RR hub to inspect it and had to use a 3-jaw puller to get it off the half shaft.

In the process I managed to pull the hub apart.

I pushed the two pieces back together and rotated the bearing. It didn't feel rough, but it wouldn't stay together either.

Any idea whether I ruined a perfectly good bearing in the process of removal, or was it bad before I got to it? I also didn't notice a washer that's supposed to be between the half shaft and the hub.

Of course, now I am looking at replacement regardless

TIA,

Jeff

(on the vibration, I grab and rotate the two half shafts in opposite directions and see a lot of movement between the two and hear clunking noises in the diff - not sure the bearing was the problem, but it may be a contributor? The vibe is bad, especially over 65)

I did pretty much the same as CSS996's write up, except I used a plastic putty knife to remove the pad. Even removed the headliner residue by rubbing with my fingers. A few pieces of pad tore during the removal. I glued them back in place with 3M spray adhesive before I applied the fabric.

I also found some graffiti under the pad. I wish I had taken a picture of it.

I bought black head liner fabric from JoAnn's fabric. I tried explaining to counter girl what I was after and she said, "oh, headliner fabric, it's over on the back wall". Matches the black cloth interior very well, and inexpensive.

Again using the 3M adhesive, I applied first long way, then perpendicular short way, then lastly diagonal allowing 10 minutes between coats on both the pad and new material. Once I had the material on and happy with the corners and ends I raided the kitchen for a small pastry roller and used that to roll out the fabric.

I laid down two lines of adhesive on the inside top the short way - parallel to the doors about 6" in on each side - to secure the pad. Tucked the top in around the edges using the putty knife for good measure.

Looks great, no more sag right in front of the mirror

I'll check out the Phoenix injector. I should do the clutch master sooner than later, especially since the price is right compared to a failure.

The car's been in my keep for two years.

Yeah, I'm famously easy on clutches. The '97 LT1 Trans Am is at 160k+ on the original clutch. I was over 200K on my 4-cyl Fox body Mustang!

Not sure how many miles are on the clutch, I suspect the clutch is original, 155k+ on it.

My fear, too, was something mechanical.

I didn't have any sort of bleeder tool to work with. What did you use to draw fluid out? From this experience, I can see how forcing fluid up through the system would work. The easiest position to get the slave into while still attached to the hose on the car was bleeder down. Slave attached to the bell housing, forget it. Bleeder is right up against the tunnel.

It just seemed strange that I didn't get any pedal with the little bleeding on the car I managed to do. Usually I manage to get something.

OK....

The fork is only about an inch inside the bell housing and I could feel the slave compress quite a bit.

I went back and did as suggested in post #3. Since I can't get parts until at least Tuesday, I thought what have I got to loose at this point. Time is about all I have.

Pulled the whole system out, did a bench bleed on the master, hooked the system together and bled. Reinstalled everything.

And, since all I have it time....

...I took that rubber cup out of the master cylinder, filled it all the way up with fluid and walked away.

This evening I could feel a little resistance in the pedal about an inch off the floor. At that point I kept pumping and pumping and pumping the pedal.

D@mn thing works now. There must have been some air in there I just wasn't getting out. I thought it really strange that I didn't get any pedal at all after bleeding. What ever I did bleed wise the first time around seemingly had no effect. That's never happened to me before. Usually I get some sort of pedal, even if it is a little spongy.

Live and learn, I guess. Pretty sure going back to post 3 above got me there.

Thanks!

'89 ZF w/original clutch to my knowledge...

Went to drive to work yesterday, no clutch pedal at all. No warning, no noises. Clutch won't disengage, the pedal has no resistance. Pushing the pedal feels the same with the clutch master attached and unattached.

A little background: the slave has been leaking for the past few/three months or so. I just keep the reservoir topped up and haven't had any issues. It did have fluid yesterday.

Thinking it was the clutch slave, I bought a new one - a cast Bendix with the bleeder at 10:00. Took pretty much forever to get the old one out and the new one in. Same result - no pedal at all.

When I removed the old slave fluid came out of the clutch side of the cylinder, so it did have an internal leak. I pushed on the clutch fork and it didn't feel loose. When i reinstalled the slave I felt for the rod to make sure it was engaging the clutch fork and felt resistance when i pushed the slave up into the bell housing.

I pulled the clutch inspection plate but I really don't know what I was looking for or expecting to find. All I saw was flywheel.

After the slave was installed and still didn't work, I pulled the clutch master off. Pushed on the rod while I held my finger over the outlet and felt pressure.

I got fluid out of the slave bleeder so I know fluid was passing through the system.

It's my daily driver for the moment, not my ideal but it is what it is.

Any ideas? I'm pretty much at wits end after thrashing for 9 hours on this thing. Would the master provide enough pressure to feel with the finger test but not provide anywhere near enough pressure to move the fluid/slave/pressure plate?

Is the L98 Dorman slave from Rock Auto cast or DOM?

The Dorman listing for a replacement slave for a 1989 references GM part number 10147848 as mentioned earlier in the thread. The Dorman L98 slave is about $20 more expensive than the LT1 slave, the Wagner about $40.

Are the slaves interchangeable between L98 and LT1 cars? Looks like I've put it off long enough; "Fill the clutch fluid and check the gas, please"

Thanks for the replies and welcome, and thank you for the confirmation on pad sizes. I didn't want to get all the old stuff off to find the new pads were the wrong size...

The car sees both street and autocross use, at least for the near future.

I used HP+ on the front, cheap autozone pads on the rear of my Firechicken. Drove that combination on the street as well as autocross. I had few issues on the street - during the cold winter months, take it a little slow and drag the brakes a bit when I first start out, after that they were fine. As for dusting, I think of it more as powder coating the wheels - it's a race car ;-) I like the Hawk's a lot.

F-bods use pad compound splits to help fight rear axle hop. No axle to hop in the IRS set up, so it looks like I'll go Hawk HP+'s on all four corners of the 'vette.


It's still a stock class car, so I'll probably pass on the bias spring.